The function type_check() in aicasm grammar code was
never used properly due to a bug.
This patch fixes it up and ensures it's only called if appropriate.

In addition the unused 16bit instruction are disabled, but left in
the code for reference.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>